Electric VLSI Design System User's Manual

Chapter 9: Tools

9-6: Routing
9-6-4: Maze Routing

The maze router replaces unrouted arcs with actual geometry. To run it, use the Maze Route command (in menu Tools / Routing). If unrouted arcs are selected when the command is issued, those connections are routed. If nothing is selected, the all unrouted arcs in the current cell are routed. Note that the router is not able to handle routes that connect more than two points, so collections of unrouted arcs that daisy-chain to multiple locations must be routed one-at-a-time.

Maze routing is done with a single arc, and cannot change layers. Therefore, if the two ends of an unrouted arc are not able to connect to a common layout arc, routing will fail.

Maze routing is done one wire at a time, and may fail if no path can be found. Therefore it may be preferable to route the unrouted wires one-at-a-time in order to better control the process.

Note also that maze routing constructs an array which is the size of the route, and searches the array for a routing path. Therefore, long wires will use large amounts of memory and time.

For an example of maze routing, open the Samples library and edit the cell "tool-RoutingMaze" (you can read the library with the Load Sample Cells Library command, in menu Help). This cell has a number of unrouted wires that can be routed.

Table of Contents